package util;

public class Pagination {
    public String toLimitClause(int totalNum) {
        //向前台提供元组总数(totalNum为0不是错误)
        this.totalNum = totalNum;
        //偏移量
        int offset = (this.pageNo - 1) * this.pageSize;
        //输出LIMIT字句，注意关键字两端的空格
        return " LIMIT " + offset + "," + this.pageSize;
    }

    public Pagination(int pageSize, int pageNo) {
        //防止扶植错误
        if (pageSize > 0) {
            this.pageSize = pageSize;

        } else {
            this.pageSize = 5;
        }
        if (pageNo > 0) {
            this.pageNo = pageNo;
        } else {
            this.pageNo = 1;
        }
    }

    public int getPageSize() {
        return pageSize;
    }

    public int getPageNo() {
        return pageNo;
    }

    public int getTotalNum() {
        return totalNum;
    }

    //每页的对象（元组）数
    private int pageSize = 5;
    //页号
    private int pageNo = 1;
    //对象（元组）总数
    private int totalNum = 1;
}
